This invention relates to a fastener to be used for securing one panel onto some other panel which has already been fixed in position.
Generally, screws are used when panels or parts are secured onto fundamental panels which have already been fixed in position. Where such fundamental panels happen to be made of metallic materials, the fastening of panels or parts is effected in some cases by means of tapping screws which are directly driven into the metal panels. In most cases, however, there are generally used fasteners made of synthetic resins for the purpose of facilitating the fastening itself and, at the same time, ensuring rigid fastening.
A good many kinds of fasteners heretofore have been suggested and actually adopted for uses of this nature.
This synthetic resin fastener is so constructed that desired fastening of an attaching panel or part onto a stationary panel is accomplished by inserting the pair of legs of the fastener into an angular fitting hole formed in advance in the stationary panel until the lower surface of the flange of the fastener comes into intimate contact with the surface of the stationary panel, then placing the attaching panel or part on the stationary panel in such a way that the fitting lug of the attaching panel or part rests fast on the upper surface of the flange, thereafter inserting a screw first through the hole punched in advance through the fitting lug of the attaching panel or part and then through the perforation in the flange, allowing the leading portion of the inserted screw to force its way between the opposed legs inserted in the aforementioned fitting hole for thereby causing the opposed legs to be diverged and pressed into tight engagement with the inner wall of the fitting hole.
The conventional fastener described above fully serves its purpose when the fitting hole in the panel is capable of thoroughly withstanding the increasing pressure exerted thereon by the legs being diverged because of the forced advance of the screw, namely when the panel in which the fitting hole is formed retains high strength as in a metal plate in spite of the aforementioned exertion of pressure. When the basal panel itself is weak as in the case of a plate made of synthetic resin, the fitting hole formed therein is spread out by the legs being diverged as described above. In this case, therefore, the fastener may at times fail to come into ample fast engagement with the legs and prove to be useless for the purpose.
Since the conventional fastener is constructed in such a way that the forward ends of the inserted legs are diverged by the forced advance of the screw and the attaching panel or part is fastened onto the stationary panel without the slightest play by having the edge of the fitting hole pinched tightly between the diverged legs and the flange, the effectiveness of the fastener hinges heavily upon the thickness of the panel. Thus, the fastener has the disadvantage that it ceases to provide effective fastening when the thickness of the panel increases beyond a certain level.
This invention has issued from a research carried out to cope with the various problems entailed by the conventional fasteners.
A major object of this invention is to provide a fastener for panels, which is not affected by the material of the basal panel so that it can be effectively used on a panel such as of synthetic resin possessed of less strength than a panel of metal and which permits a greater change in the panel thickness than the conventional fasteners of a similar kind.
Another object of this invention is to provide a fastener for panels, which permits desired fastening of an attaching panel or part to the stationary panel to be effected without suffering the fitting hole formed in the panel to be enlarged in diameter owing to the insertion of the fastener.
A further object of this invention is to provide a fastener for panels, which is so designed that the fastener composed of substantially two members will be integrally molded of synthetic resin to suit mass production.